//
//  main.c
//  hhuc
//
//  Created by 杨霖韬 on 2018/10/24.
//  Copyright © 2018 杨霖韬. All rights reserved.
//

#include <stdio.h>
#include <stdlib.h>
int main() {
    int i,j;
    int x=0;
    int y=5;
    
    int velocity_x=1;
    int velocity_y=1;
    int left=0;
    int right=20;
    int top=0;
    int bottom=10;
    while (1)
    {
        x=x+velocity_x;
        y=y+velocity_y;
        system("cls");
        for (i=0; i<x; i++)
            printf("\n");
        for (j=0; j<y; j++)
            printf(" ");
        printf("o");
        printf("\n");
        if ((x==top)||(x==bottom)) {
            velocity_x=-velocity_x;
        }
        if ((y==left)||(y==right)) {
            velocity_y=-velocity_y;
        }
    }
    return 0;
}
